1. Field
The invention relates to fluid spray devices and trigger mechanisms therefore, and more specifically to water spray guns and water spray wands such as used for gardening with trigger mechanisms which lock to maintain the flow of water.
2. State of the Art
Water spray devices such as pistol grip water spray guns and water spray wands are used by gardeners such as to water gardens and lawns. Such devices typically connect to the male threaded connector end of a standard garden hose and include a trigger mechanism to actuate a valve which controls the flow of water therefrom. Various removable nozzles can typically be attached to the same basic spray device to provide the desired water spray pattern to fit the particular spray application. Some of such water spray devices have trigger mechanisms and valves which permit the flow of water to be infinitely varied from no flow to full flow. Others are merely allow no flow and full flow with no variability therebetween.
There are a number of water spray guns which are of the pistol grip type, several being disclosed in U.S. Pat. Nos. 5,967,421, 5,967,422, and 6,007,003 all of which are issued to Wang. The basic water spray gun disclosed in those patents which includes a housing having a lower grip portion and an upper spray portion angled to the grip portion, and a trigger receiving chamber at the front of the grip portion. A water passageway extends completely through the housing, the end of the grip portion having a female threaded portion adapted to be threadably secured to the male threaded connector of a standard garden hose and the end of the spray portion adapted for connecting a water spray nozzle. A trigger receiving chamber is formed at the front portion of the grip portion of the housing. The water spray gun further includes a linearly actuated valve which includes a resilient valve seat which fits within the water passageway at an annular shoulder thereof, a slidable valve member with a pointed nose portion and annularly tapered seat which matingly fits with the valve seat, a compression spring to bias the valve member toward the valve seat, and a screen spring retainer to retain the spring within the water passageway. A trigger mechanism of the water spray gun includes a hollowed trigger having an upper notch and lower actuation post extending rearwardly from a front wall thereof, which trigger is pivotally mounted partially within the chamber at respective upper ends of respective sidewalls thereof, a headed slide pin having respective headed and pointed ends and a pair of annular O-rings and grooves, which slide pin slidably fits within a tubular post of the housing which fluidly connects with the water passageway with a compression spring therebetween to bias the slide pin forwardly against the actuation post of the trigger, and a hollowed trigger lock having a tubular post which extends rearwardly from a front wall thereof over a stepped post of the housing with a compression spring therebetween to bias the trigger lock forwardly. When the trigger is depressed toward the housing, the post thereof pushes the pointed end of the slide pin into contact with the pointed end of the slide valve so as to move the seat thereof away from the valve seat so as to allow water flow through the water passageway. The trigger lock includes a downwardly and rearwardly sloped lower face which abuts a lower edge of the notch of the trigger such that as the trigger is depressed and pivots, the trigger lock is also depressed so as to lock the trigger in the full on water spray position. The trigger lock is released by further depressing the trigger lock which allows the trigger to return to the undepressed position so as to stop the flow of water.
One version of the trigger lock is disclosed in the '421 patent which includes a non-textured, smooth sloped lower face, or micro-adjustment slope face. In practice, such slope face provides only for full water flow rather than any adjustability of the water flow as the sloped lower face relies on friction alone for locking and does not provide adequate holding force to maintain the desired rate of water flow. Another version of the trigger lock is disclosed in the '422 patent which includes a smooth sloped lower face having a pair of longitudinal slits therein so as to form a resilient pushing section, or tab, having a guide edge at the free end thereof. This second version is evidently an attempt to overcome such shortfalls of the first version trigger lock yet still does not provide adequate frictional force to maintain the desired water flow rate. Yet another version of the trigger lock is disclosed in the '003 patent which includes a zig-zag or stepped sloped lower face wherein the stepped configuration thereof is to allow the trigger lock to move in a more precise, stepwise manner to micro-adjust the water amount in a stepwise manner rather than merely relying on friction between the sloped face and the edge of the trigger hold the position thereof.
There is a need for a fluid spray device such as for spraying water and a trigger locking mechanism which allows true incremental locking and flow control of the fluid.